In my aforesaid co-pending application there are disclosed several embodiments of a percussion apparatus, especially suitable in respiratory therapy, to mobilize fluids in a patient's lungs, and for treatment of cystic fibrosis. Particularly, the apparatus includes a reciprocating member exposed to first and second gas chambers, in which a gas sealing means provides a gas-tight seal between the chambers. Gas accumulates in the first chamber until the pressure is sufficient to force the seal open, and the gas flows into the second chamber, to initiate the reciprocating motion. A gas outlet passageway communicates with the second gas chamber to then vent the gas from the apparatus.
A disadvantage of that apparatus results when the gas-tight seal is opened and the first and second chambers are in communication because gas introduced into the apparatus from a supply source continues to flow from the first chamber into the second chamber and out through the gas outlet passageway. This flow will continue until the gas-tight seal is again formed as the reciprocating member returns to its original position. Such a continuous flow of gas results in a substantial and unnecessary gas usage in operating such a device.
In my co-pending application Ser. No. 223,355, filed Jan. 8, 1981, (#20) there are disclosed embodiments of a percussor in which a movable gas sealing member alternately opens and closes communication between a gas pressure chamber, and a gas outlet passageway. When the gas seal is open, gas continues to flow into the gas pressure chamber and out through the gas outlet passageway, also resulting in more gas usage than is required to achieve the percussive effect of the apparatus. It is to the elimination of such excessive gas usage and to improve efficiency of the aforesaid percussor apparatus that the present invention is directed.